The only time it would be over for Bitcoin is if:

- Quantum computing manages to crack the SHA-256 hashing and Elliptic Curve Digital Signature (ECDS) algorithms, and decrypt everyone's private keys.

Having said this, by the time quantum computing manages to potentially compromise Bitcoin's network, developers behind the blockchain would incorporate quantum-resistant principles or possibly move to a new chain with these QR characteristics.

- Draconian, fully-fledged attacks on Bitcoin around the world by every government.

The fact that El Salvador and CAF have made this legal tender, and most likely more countries down the track, makes me believe that this is unlikely to occur, at least not for the foreseeable future. However, I could be wrong.

- A 51% attack on the network: Theoretically possible, but extremely unlikely in practice.

Consider these resources for more info about what I am saying.

https://www.youtube.com/watch?v=wlzJyp3Qm7s&t=312s

https://www.youtube.com/watch?v=ncPyMUfNyVM

https://www.youtube.com/watch?v=-ZTGmTjqXEU

This one here is my favourite from Andreas Antonopoulos.

P.S. Yes, I know these are all from the same source, but he is one of the most knowledgeable and respected Bitcoin and blockchain experts out there.